Hi
I`ve A6 C6 2.0 tdi, on vcds scan it shows all 4 glow plugs electrical fault no other faults.
car starts no problem (when cold it takes longer and when it starts shudders for about 8 seconds and a bunch of smokes comes out of exhaust which smelling pretty rich..but after 10 seconds smokes disappears but shuddering exists every 3 seconds like pulsing just not that bad as in beginning)

Is my Injector/Glow plug Loom is faulty?
For smoking is it could be a TANDEM PUMP which is leaking? coz when i did change the fuel filter (5months ago) was DIRTY AS HELL, AND A LOT OF OIL IN IT.